package com.atguigu.client;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.SelectionKey;
import java.nio.channels.Selector;
import java.nio.channels.SocketChannel;
import java.nio.charset.StandardCharsets;
import java.util.Iterator;
import java.util.Set;

/**
 * className: ClientThread
 * description:
 * date: 2023/3/10 0010-17:10
 * <p>
 * project: nio
 * package: com.atguigu.client
 * email: 1085844536@qq.com
 * version:
 *
 * @author WangGuojian
 */
public class ClientThread implements Runnable {

    private final Selector selector;

    public ClientThread(Selector selector) {
        this.selector = selector;
    }

    @Override
    public void run() {
        try {
            for (; ; ) {
                // 获取 channel 数量
                int readChannels = selector.select();

                if (readChannels == 0) {
                    continue;
                }

                // 获取可用的 channel
                Set<SelectionKey> selectionKeys = selector.selectedKeys();
                // 遍历集合
                Iterator<SelectionKey> iterator = selectionKeys.iterator();
                while (iterator.hasNext()) {
                    SelectionKey selectionKey = iterator.next();

                    // 移除 set 集合当前 selectionKey
                    iterator.remove();

                    // 如果可读状态
                    if (selectionKey.isReadable()) {
                        readOperator(selector, selectionKey);
                    }
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    /**
     * 处理可读状态操作
     *
     * @param selector     {@link Selector}
     * @param selectionKey {@link SelectionKey}
     */
    private void readOperator(Selector selector, SelectionKey selectionKey) throws IOException {
        // 1.从 SelectionKey 获取到已经就绪的通道
        SocketChannel socketChannel = (SocketChannel) selectionKey.channel();

        // 2.创建 buffer
        ByteBuffer byteBuffer = ByteBuffer.allocate(1024);

        // 3.循环读取客户端消息
        int readLength = socketChannel.read(byteBuffer);
        StringBuilder message = new StringBuilder();
        if (readLength > 0) {
            // 切换模式
            byteBuffer.flip();

            // 读取内容
            message.append(StandardCharsets.UTF_8.decode(byteBuffer));
        }

        // 4.将channel 再次注册到选择器上，监听可读状态
        socketChannel.register(selector, SelectionKey.OP_READ);

        // 5.把客户端发送消息，广播到其他客户端
        if (message.toString().length() > 0) {
            // 广播给其他客户端
            System.out.println(message);
        }
    }
}
